This invention relates to wheels for land vehicles and more particularly to wheels having spring-biased feet that retract when in contact with a road or other traveled surface. Such wheels are especially useful on vehicles for operating on rough terrain such as farm, construction and military equipment.
Spring wheels have been designed for use on automobiles, trucks and the like wherein the main consideration has been the provision of proper resiliency for smooth riding. Such wheels usually embody a tread portion formed of sections arranged end-to-end circumfirentially of the wheel and yieldingly supported for independent inward movement to obtain a cushioning effect. These prior art wheels are merely intended to be substitutes for pneumatic tires, the feet thereof exihibiting a minimum amount of deflection. These wheels are therefore of limited utility over rough terrain.
In my U.S. Pat. No. 4,108,231 there is disclosed a wheel comprising a hub and means defining a plurality of chambers equally spaced around the hub. A foot, which is disposed in each chamber, is capable of radial movement therein, that portion of each foot nearest the hub having at least one cavity therein. Means including a threaded rod are provided for restricting the movement of each of the feet beyond a predetermined distance from the hub so that those portions of the feet remote from the hub tend to lie in a substantially circular arc. At least one spring is disposed between each foot and the hub, one end of the spring being fixedly mounted with respect to the hub and the other end being disposed within the cavity of the associated foot. To remove a foot to replace a spring, for example, the tread had to be removed and the threaded rod had to be removed. This was a somewhat time consuming task. Furthermore, it was found that the forward and rearward surfaces of the chamber walls caused wear on the adjacent surfaces of the feet.